An instant camera of the general type indicated above is disclosed in U.S. Pat. No. 4,664,497 to Johnson et al. This patent describes a photographic camera enclosing a film cassette supported in an exposure position. A lighttight imbibition or storage chamber is located behind or below the film cassette support into which an exposed film unit is moved and remains during the formation of a visible image.
An outer or lower wall of the chamber has a film loading door with a window therein for viewing an exposed film unit after a predetermined period while it is located in the imbibition chamber. A blind is provided in association with the window and is movable from a normal lighttight covering position over the window to an uncovering position to permit viewing of the film unit. With this arrangement, sequentially exposed film units are moved into the imbibition chamber and positioned in superposed relationship in that chamber, the last film unit being outermost or lowermost and nearest the window.
A manually operable button is provided on the lower wall to move a slide plate carrying a film unit engaging end. The film unit engaging end is configured to move all of the film units from the imbibition chamber via an egress opening to a position where the operator may grasp them and complete their removal.
With this arrangement, when an exposed film unit is moved into the imbibition or storage chamber, it may cause a previously exposed film unit already in the chamber to be moved partially out of the chamber through the egress opening due to the sliding frictional engagement between the outermost or lowermost film unit and the adjacent superposed film unit. There is no positive lock to prevent the partial ejection of a developing film unit as the newly exposed film unit is delivered to the lighttight chamber. Also, with this arrangement there is no adequate means for preventing actuation of the button to remove an exposed film unit during the desired "dark period" when it is being processed in the camera.